Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process

Definitions

• the invention relates to a method for the manufacture of a cold-rolled steel strip in thin and super-thin strip thicknesses for producing stretch-formed cans or other deep-drawn parts, in which after annealing the strip is further heat treated with a liquid which contains both a phosphatizing medium and a lubricant.
• phosphatized sheet metal that is, sheet metal, which is provided with a thin phosphate coating
• the phosphatizing must be effected by a special operation and subsequently the phosphatized sheet metal must still be provided with an oil film which prevents rusting of the sheet metal and furthermore acts as a lubricant during the deep drawing. Due to these additional method steps, the phosphatized sheet metal cannot be manufactured at any appreciably less cost than tin-plated sheet metal.
• an acid reaction lubricant is known under the term Bonderlube 460 and 461 (Registered Trademark).
• Bonderlube 460 and 461 is sold by Metallgesellschaft AG Frankfurt (Main). It contains both a phosphatizing medium and a lubricant.
• the annealed steel strip is dipped for a substantial period of time into the liquid, which liquid contains the phosphatizing medium and the lubricant.
• the bath temperature is normally at 65°-70° C., and the dipping time is approximately 10 minutes. After the treatment, the treated strip must hang for approximately 5 minutes above the bath container so that most of the excess lubricant can run off.
• the strip Prior to the further deformation, the strip is permitted to assume room temperature in an inclined position.
• both a phosphate layer and also a lubricant layer is produced in the strip.
• the phosphate layer has the characteristic of better holding of the lubricant and the lubricant serves to protect against rust.
• the lubricant acts to protect against rust.
• the basic purpose of the invention is to improve a method for the manufacture of a cold-rolled steel strip in thin and super-thin strip thicknesses for producing stretch-formed cans or other deep-drawn parts of the above-mentioned type in a less expensive manner than was previously known.
• the strip in the new method does not remain during the entire reaction time, which is required for the phosphatizing, in the liquid bath which is heated to the necessary temperature, but instead, liquid containing the phosphatizing means and the lubricant is applied to the still hot strip and then the strip is rolled up with a still wet liquid film.
• the actual phosphatizing reaction then takes place in the rolled-up roll. Since such a steel strip roll having some tons of weight cools relatively slowly, there is sufficient reaction time available without the special techniques previously required.
• the strip can run with the usual speed through the continuous annealing furnace and is subsequently cooled only so far that it still has the heat necessary for the reaction.
• the heat which is fed to the strip for the annealing operation is thereafter used partly for heating the liquid and for maintaining the temperature which is necessary for the phosphatizing reaction. It is therefore also not necessary to bring the reaction liquid to the required temperature of 65° - 70°, but same can be applied at room temperature advantageously through roller application or through spraying on the strip. It is also possible if desired to permit the strip to dip into a liquid bath for a short distance. In any case, the previously required heating and maintaining of the temperature of the liquid bath is no longer needed.
• the phosphate layer protects together with the oil the steel strip against corrosion until it is further processed. During the further processing through stretch forming or deep drawing, the phospate layer acts as a separating layer and the oil as a lubricant.
• the temperature must be so controlled that the liquid does not evaporate or dry as the steel strip together with the yet wet liquid film is rolled up. However, it must be sufficient so that during the cooling time of the steel strip roll, the necessary reaction temperature is actually available. The larger the steel strip roll, the longer is its cooling-off time.
• the strip is advantageously, after the annealing and prior to the application of the liquid, cooled to a temperature of approximately 100° C. This assures that on the one hand the liquid does not evaporate or dry and on the other hand during the reaction time that the necessary reaction temperature is present.
• the strip after being rolled up is further processed without cold finishing (dressing).
• dressing On the one hand the separate operation of the dressing is thus eliminated and on the other hand it has been found that such a nondressed steel plate is just as suitable for the stretch forming as a dressed steel strip. This, however, does not prevent the steel strip from being subjected if desired to a dressing procedure prior to being processed in the punch-drawing press or a cup-drawing press, which dressing procedure serves only to overcome unevennesses and the roll twist of the strip.
• the strips is treated in a liquid which contains both a phosphatizing medium and a lubricant.
• Phosphatizing media are diluted solutions of acid zinc phosphate in which phosphoric acid and oxidizing agents (nitrate and the like) are mixed.
• phosphoric acid and oxidizing agents nitrate and the like
• the treatment time required for the phosphatizing is materially shortened.
• This method can, however, only be used if the strip is further treated as quickly as possible after the phosphatizing in order to prevent the strip from corroding between the phosphatizing and the further treatment.

Landscapes

• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Treatment Of Metals (AREA)
• Heat Treatment Of Sheet Steel (AREA)
• Lubricants (AREA)
• Electroplating Methods And Accessories (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=5909343

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (2)

Citations (3)

• 1974
  • 1974-04-12 US US05/460,609 patent/US3982968A/en not_active Expired - Lifetime
• 1975
  • 1975-02-18 BE BE153461A patent/BE825663A/xx not_active IP Right Cessation
  • 1975-03-04 IT IT67544/75A patent/IT1030261B/it active
  • 1975-03-07 FR FR7507188A patent/FR2263311A1/fr not_active Withdrawn
  • 1975-03-07 GB GB962375A patent/GB1438477A/en not_active Expired
  • 1975-03-07 JP JP50027931A patent/JPS587711B2/ja not_active Expired
  • 1975-03-07 CA CA221,579A patent/CA1044123A/en not_active Expired
  • 1975-03-07 NL NL7502767A patent/NL7502767A/xx not_active Application Discontinuation

Patent Citations (3)

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